The present invention relates to a driving condition control method and system installed in a vehicle, which are capable of controlling the driving conditions of the vehicle.
Conventional techniques for causing a target torque to follow up a change of an accelerator pedal's operating state by a driver's operation are disclosed in Japanese Unexamined Patent Publication No. H09-242862 and in Japanese Unexamined Patent Publication No. H10-329585.
The technique disclosed in the former publication estimates the rising slope of a road surface according to accelerating resistance torque. The technique corrects the gear ratios of the automatic transmission (AT) of a vehicle, thereby keeping torque during the running of the vehicle on the rising slope of the road surface.
The technique disclosed in the later publication obtains a steady target torque of a driving system of a vehicle according to a driving condition of the vehicle, and determines a sequential waveform of a transient state of the target torque according to variation of the steady target torque within a predetermined control period.
The technique also obtains sequential data representing fluctuations of the target torque, and obtains the fluctuations of the target torque. The technique adds the obtained fluctuations of the target torque to the previous transient target torque to obtain a present transient target torque. The technique performs a transient control of the target torque while the steady target torque fluctuates.
On the other hand, another technique disclosed in Japanese Unexamined Patent Publication No. 2000-297664 prevents, when the operating state of an accelerator pedal of a vehicle by the driver is kept constant, a shock from occurring in the vehicle according to sudden change of the driving resistance of the vehicle. In particular, the technique estimates a driving resistance according to the vehicle speed and the vehicle acceleration to determine the target torque based on the estimated driving resistance.
These disclosed techniques, when the vehicle runs on a road surface that makes it difficult to obtain a desired torque, increase the command power with respect to the engine, thereby obtaining the desired torque.
Even when the vehicle runs on a road surface that causes the vehicle's torque to be lost, these techniques increase the command torque so that the loss of the torque may more increase.